Publications such as WO96/036273 (Nov. 21, 1996), WO04/093672 (Nov. 4, 2004), and WO04/080276 (Sep. 23, 2004), etc. describe related technology. WO96/036273 and WO04/093672 disclose basic operation principle for visualizing the structure of a hypodermic vein, the types of usable light sources, and detectors. The publications describe a similar method to the present invention, a method of illuminating the skin with light ranging from ultraviolet to infrared by using the corresponding light sources, filtering the reflected or transmitted light by using a filter with a narrow transmission band, and visualizing the image by using various detectors and using a goggle or a projector. All of the publications report that light in the near-infrared region, which penetrates the skin best and obtains maximum absorption of blood, is the most effective light source, and anticipate that a intensifier tube, CCD, CMOS, etc. may be used as a detector.
In addition, PCT/US2004/005669 filed by Luminetx Corporation discloses a device for facilitating diffusion of infrared light so as to provide uniform illumination. Said device has a complex light source structure to induce the diffusion of infrared light and induce scattered reflection to distribute light uniformly. However, the device not only involves a complex manufacturing process, but also poses a structural obstacle in the manufacture of a product due to its structure.
In addition, devices according to conventional technology can display a life-size image only, and thus it is difficult to see capillaries while using them. In addition, the devices also have a disadvantage of providing a monochromatic image only.